Pneumatic cement gun machine

ABSTRACT

A cement gun machine has a hopper subtended by a rotary transport bowl which is divided into radial compartments. The bowl receives dry cement mixture from the hopper, and moves it to a station where the mixture is pneumatically discharged into a delivery hose. A hood structure within the hopper traps cement dust and prevents it from escaping into the ambient atmosphere. Means are provided for introducing measured quantities of accelerator material into the cement mixture in the transport bowl.

[451 June 27, 1972 United States Patent Burtin 259/147 ....259/l47 Kempthorne ..........................259/l47 1,731,953 10/1929 Thomson............,.................. 2,637,539 5/1953 Crom............. 3,096,968 7/ 1963 Primary Examiner-Robert W. Jenkins Attorney-Cohn and Powell [73} Assignee: Detroit Tool and Engineering Company,

Lebanon, Mo.

[22] Filed: April 15, 1971 Appl ABSTRACT A cement gun machine has a hopper subtended by a rotary transport bowl which is divided into radial compartments. The

[52] U.S.Cl.....

bowl receives dry cement mixture from the hopper, and moves Mu -.-l 0 d M .mF N B it to a station where the mixture is pneumatically discharged into a delivery hose. A hood structure within the hopper traps cement dust and prevents it from escaping into the ambient at- References Cited mosphere. Means are provided 7 for introducing measured quantities of accelerator material into the cement mixture in the transport bowl.

UNITED STATES PATENTS 1,663,206 3/1928 MacRae.................................259/l47 l4Claims,7Drawin gFigures F iii:

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cum MPMQQ ATTORNEYS PNEUMATIC CEMENT GUN MACHINE BACKGROUND OF THE INVENTION operated in an enclosed space, in a mine or tunnel, wherein the shotcrete process is widely employed for lining wall surfaces with cement. The present invention stems from the need for reducing the particulate matter that normally escapes from shotcrete machines of heretofore prevailing construction, whereby to improve atmospheric conditions in the vicinity of the machines.

Another achievement of the present invention is the provision of improved means for introducing an accelerator agent into the cement mix in a way that reduces tendency of the cement to cake while in the machines, or to foul machine surfaces.

SUMMARY OF TI-IE INVENTION In a concrete gun machine of the character described, including a hopper providing a mixing chamber and rotary bowl having radial compartments for receiving and conveying the material to apressurizing zone below a fixed sealing plate, means are provided for preventing pressurized air that may be carried with the rotating distributor bowl beyond the discharge port from escaping to the outside atmosphere through the body of material in the hopper.

Accordingly, it is an object of the present invention to prevent the dry constituents in the mixing chamber of the hopper from being discharged from the hopper into the atmosphere during the operation of the machine.

Another object is directed to improvements for facilitating assembly and disassembly of the machine as for cleaning and servicing purposes.

Yet another object resides in improved provisions for depositing metered quantities of an additive to the cement mixture for purposes of accelerating the setting time mixture.

These and other objects and advantages of the invention from the following detail description and the accompanying description of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a prospective view of the machine of the invention with portions thereof removed for purposes of illustration;

FIG. 2 is a sectional view taken at a vertical plane indicated by line 2-2 ofFIG.

FIG. 3 is a top plan view of the transport bowl;

FIG. 4 is a perspective view of the lower hopper section with certain discharge fittings separated therefrom for purposes of illustration;

FIG. 5 is a side elevational view of the machine;

FIG. 6 is a side elevational view, partly in section, of the auxiliary hopper for accelerator material, and

FIG. 7 is a sectional view taken at line 7-7 of FIG. 6.

DETAILED DESCRIPTION described, are detachable from the base plate but normally rigidly connected thereto by suitable means, such as the wedge clamp provision indicated at 15. The means shown include a wedge block 15a on the hopper wall, which block is moved, when the hopper is turned relative to the base plate, into and out of wedging engagement with the arm of a C- clamp 15b on that plate.

Mounted for rotation within the lower section 13a of the hopper is a transport bowl 16 that carries small batches of the dry mix from a chute at one side to a discharge station at the opposite side of the hopper. Bowl 16 is formed to provide an annular chamber which is divided by radial partitions 17 into a ring of radial pockets 18. The pockets 18 have rounded bottoms 19. An annular partition 20 transversely intersects the pockets 18 and extend downwardly therein to a plane spaced above the rounded pocket bottoms 19. Accordingly, the bowl pockets 18 are, in effect, U-shaped passages with outer legs designated 18a and inner legs 18b, which terminate in upwardly facing openings 22 and 23, (FIG. 3), respectively.

Removably disposed on the top surface of the bowl 16 is a circular wear-plate 24 having the form of a grid, the plate 24 being provided with rings of outer and inner openings that conform in size and shape to the immediately underlying openings 22 and 23 of the bowl hopper 16.

The distributor bowl l6 and its wear-plate 24 are mounted on and keyed to the upper end of a vertical drive shaft 27 that projects upwardly through the base plate 10. Below plate 10 within a housing 28 are transmission means 29 that operatively interconnect shaft 27 with a drive motor 30, (FIG. 5). Motor 30, mounted on the rear deck of the base, provides power for driving the shaft 27 and other operating parts to be subsequently described. Shaft 27 has a threaded stud at its upper end to receive the base portion 32 of a vertical agitator post 33. The said post is provided with a pair or more of paddles or agitator arms 34, these being located in the central region of the upper hopper section 13b. The agitator post 33 has an integral cap block 33a formed to provide flat, wrenchreceiving surfaces that facilitate the securement and removal of the post from the drive shaft. The base 32 of the post functions to clamp the transport bowl and its wear-plate in place onto the drive shaft 27.

Cement mix in the hopper is introduced into the bowl pockets only through the outer ring of o enings 22, and is precluded from entering the inner openings 23 by a hood structure, as best appears in FIG. 1. The hood structure has a top plate 35 which is spaced above the distributor bowl and is fixed, as by welding, to the hopper wall, in the plane of the junction between the upper and lower hopper sections 13a and 13b. Plate 35 constitutes a floor for the upper portion of the hopper and has an arcuate marginal recess or opening 36 through which the mix in the hopper drops into the chute 37, and therefrom to and through the bowl openings 22. Chute 37 is formed between the hopper side wall and a skirt 38 that depends from the top plate 35. Its lower edge lies in close proximity to, or in light contact with, the ring portion 240 of the wear-plate. The chute 37 has end walls that extend radially from the end edges of the skirt 38 to the outer wall of the hopper. Circumferentially, the chute 37 extends through an arc of approximately The top plate 35 of the hood has a circuit central opening to accommodate the agitator post, and a short up-standing tube section 40 fixed to the plate coacts with a cup-shaped cap 41 on the agitator post, to prevent cement mix from entering the space within the hood structure. The cap 41 rotates with post 33 and has radial agitator arms 42 that augment movement of the mix into the chute 37.

The rotating transport bowl 16 moves the cement mix in the bowl pockets to a discharge compartment 43, (FIG. 4) located within the hood structure diametrically opposite the chute 37. Compartment 43 is generally wedge-shaped in plan and spans an angle of about 45, encompassing several pairs of the bowl openings 22, 23. The compartment 43 is fronted by a rectangular opening in the lower hopper section, and is formed by and between radial side walls 430 and an inner or back wall 43b. These compartment walls are welded to, and extend downwardly from the hood top plate and their lower margins closely approach the upper surface of the bowl wear-plate.

Disposed within compartment 43 is a discharge head 45, comprising a wedge-shaped orifice plate 36 having two openings therein that register respectively with the bowl openings 22 and 23. Pipe fittings 49 and 50 are mounted on the orifice plate with their inner ends in communication respectively with the plate openings. The discharge head 45 is detachable from the hopper and is normally held in place by clamps, one thereof, indicated at 52, comprising a clamp screw 52a, and a threaded collar 52b which is welded to the hopper wall. Clamp 52a is angularly arranged to have its lower end bear downwardly upon the orifice plate 46 with sufficient pressure to provide an effective seal between orifice plate and wear-plate 24 without placing an undue frictional load on the rotating bowl. Another clamp includes a screw part 53a and a clamp member 5312 arranged to prevent the orifice plate from working out of the discharge compartment.

The pipe fitting 49 is connected to an air pressure hole 54, and pipe fitting 50 is connected to the hose for conducting the cement mix, blasted from the bowl pockets and into pipe 50, to a discharge nozzle, not shown. Water from a separate hose is injected into the stream of discharging cement mix at the nozzle.

An undesirable condition heretofore attending the operation of concrete gun machines of the type described herein is that pressurized air is carried by the rotating bowl beyond the discharge station and released into the body of cement mix in the hopper. The leakage air, escaping through the open top of the hopper, carries with it the fines of the cement mix and creates a severe dust condition in the vicinity of the machine. The dust laden atmosphere presents a serious health hazard to the operating personnel. The condition is aggravated where the machines are used in closed areas, as in mine shafts and tunnels, an application where guncreting, except for the above noted fault, has proven an effective and efficient method for producing a cement lining shell on the wall surfaces.

in the machine of the present invention, leakage air is trapped by the hood structure, and prevented from entering the cement mix in the hopper. Air and cement dust that finds its way into hood space is evacuated therefrom to a suitable dust collector. Numeral 60 designates a pipe fitting which is in communication with the suction line leading to interior of the hood and connected to a dust collector (not shown).

Another novel and improving feature of the present invention is the provision of means for introducing measured quantities of an accelerator agent to the concrete mix. Accelerator agents for concrete and cement are well known and used in the trade. Such agents cause the cement to set up very rapidly following the addition of water to the mix, and use thereof is especially desirable where the cement is being applied to a wall or ceiling surface.

In the present example there is provided an auxiliary hopper 70 (FIGS. 5 and 6) for holding a supply of the accelerator material. Hopper 70 is or may be mounted on the side of the main hopper 13. Operating within the hopper 70 is a vertical shaft 71 on which is mounted, within the base of the hopper, a shutter disc 72 for controlling and regulating the flow of the accelerator material to a discharge port 73 in the floor of the hopper. The shaft 71 is geared or belted to the drive shaft 27 for the main hopper, so that plate 71 operates to release measured batches of accelerator material in timed relation to the movement of the transport bowl 16.

A conduit 74 conducts the accelerator agent to the transport bowl, its discharge end being located immediately above the bowl openings 22. Agitator blades 75 are securedto and rotated by the shaft 71. It will appear that measured quantities of the accelerator agent are added to the cement mix in the transport bowl shortly before the material is expelled therefrom. The minimal time that the accelerator is in contact with the mix while in the machine reduces the tendency of the mix to cake and foul surfaces of machine parts.

I claim as my invention:

l. A cement gun machine comprising:

a. a hopper for cement mixture,

b. a rotary transport bowl underlying the hopper,

c. drive means for said transport bowl,

d. a discharge tube,

e. pneumatic means for expelling cement from said bowl into said discharge tube, and

f. a hood within said hopper providing a substantially closed chamber above the transport bowl, said bowl preventing air from said pneumatic means from escaping upwardly through the body of said cement mixture in said hopper.

2. A cement gun machine as set forth in claim 1 including an exhaust pipe communicating with said chamber.

3. A cement gun as set forth in claim 1, wherein: the transport bowl includes partitioning means defining radial, U- shaped pockets subtending inner and outer rings of openings, said hood having wall portions defining a chute for conducting cement mixture to the transport bowl through its said outer ring of openings.

4. The cement gun of claim 1 wherein said hood has a top wall having a central opening, an upstanding collar on said top wall extending around said opening, an agitator post extending vertically from said transport bowl and through said collar, a closure cap surrounding said collar, mounted on said agitator post, and agitator blades carried by said post and overlying the top wall of the hood.

5. The cement gun machine of claim 1 wherein said hood includes wall portions forming a chute at one side of the hopper, leading to the transport bowl, and wall portions at the opposite side of the hopper defining a cement discharging compartment.

6. A cement gun machine as set forth in claim 1 including an auxiliary hopper for accelerator material, said auxiliary hopper being adapted and arranged to release accelerator material therefrom to the cement mixture in the machine.

7. A cement gun machine as set forth in claim 6 wherein said auxiliary hopper is provided with agitator means operatively connected to the drive means for the transport bowl.

8. A cement gun machine as set forth in claim 1, including an auxiliary hopper for cement accelerator material, and a conduit for conducting material from said auxiliary hopper into the transport bowl.

9. A cement gun machine as set forth in claim 8, including means operatively connected to the transport bowl for controlling the ilow of accelerator material delivered thereto.

10. A cement gun machine comprising:

a. a hopper for dry cement mixture,

b. a rotary transport bowl below the hopper,

c. drive means for said transport bowl,

d. means forming a chute for conducting mixture from the hopper to said transport bowl,

e. pneumatic means for discharging mixture from the bowl,

f. an auxiliary hopper for cement accelerator material,

g. and conduit means for conducting accelerator material from said auxiliary hopper to the transport bowl.

1 1. The cement gun machine set forth in claim 10 including means for controlling the flow of accelerator material from said container to the transport bowl.

12. The cement gun as set forth in claim 1 1 wherein the flow control means for accelerator material is operatively connected to the drive means for said transport bowl.

13. The cement gun machine as set forth in claim 10 wherein said conduit means conducts accelerator material into the transport bowl at a point adjacent to the point of discharge of the cement mixture from the transport bowl.

14. A cement gun machine comprising:

a. a main hopper for cement mixture,

b. a rotary transport bowl,

c. drive means for rotating said transport bowl,

d. passage means for conducting mixture from said hopper into the transport bowl,

e. pneumatic means for expelling the cement mixture from said transport-bowl,

f. an auxiliary hopper for holding accelerator material to be added to the cement mixture in the machine,

g. and valve means operatively connected to said drive means for coordinating the rate of flow of cement accelerator material with the rotation of said transport bowl.

' i I! l '8 *l 5 

1. A cement gun machine comprising: a. a hopper for cement mixture, b. a rotary transport bowl underlying the hopper, c. drive means for said transport bowl, d. a discharge tube, e. pneumatic means for expelling cement from said bowl into said discharge tube, and f. a hood within said hopper providing a substantially closed chamber above the transport bowl, said bowl preventing air from said pneumatic means from escaping upwardly through the body of said cement mixture in said hopper.
 2. A cement gun machine as set forth in claim 1 including an exhaust pipe communicating with said chamber.
 3. A cement gun as set forth in claim 1, wherein: the transport bowl includes partitioning means defining radial, U-shaped pockets subtending inner and outer rings of openings, said hood having wall portions defining a chute for conducting cement mixture to the transport bowl through its said outer ring of openings.
 4. The cement gun of claim 1 wherein said hood has a top wall having a central opening, an upstanding collar on said top wall extending around said opening, an agitator post extending vertically from said transport bowl and through said collar, a closure cap surrounding said collar, mounted on said agitator post, and agitator blades carried by said post and overlying the top wall of the hood.
 5. The cement gun machine of claim 1 wherein said hood includes wall portions forming a chute at one side of the hopper, leading to the transport bowl, and wall portions at the opposite side of the hopper defining a cement discharging compartment.
 6. A cement gun machine as set forth in claim 1 including an auxiliary hopper for accelerator material, said auxiliary hopper being adapted and arranged to release accelerator material therefrom to the cement mixture in the machine.
 7. A cement gun machine as set forth in claim 6 wherein said auxiliary hopper is provided with agitator means operatively connected to the drive means for the transport bowl.
 8. A cement gun machine as set forth in claim 1, including an auxiliary hopper for cement accelerator material, and a conduit for conducting material from said auxiliary hopper into the transport bowl.
 9. A cement gun machine as set forth in claim 8, including means operatively connected to the transport bowl for controlling the flow of accelerator material delivered thereto.
 10. A cement gun machine comprising: a. a hopper for dry cement mixture, b. a rotary transport bowl below the hopper, c. drive means for said transport bowl, d. means forming a chute for conducting mixture from the hopper to said transport bowl, e. pneumatic means for discharging Mixture from the bowl, f. an auxiliary hopper for cement accelerator material, g. and conduit means for conducting accelerator material from said auxiliary hopper to the transport bowl.
 11. The cement gun machine set forth in claim 10 including means for controlling the flow of accelerator material from said container to the transport bowl.
 12. The cement gun as set forth in claim 11 wherein the flow control means for accelerator material is operatively connected to the drive means for said transport bowl.
 13. The cement gun machine as set forth in claim 10 wherein said conduit means conducts accelerator material into the transport bowl at a point adjacent to the point of discharge of the cement mixture from the transport bowl.
 14. A cement gun machine comprising: a. a main hopper for cement mixture, b. a rotary transport bowl, c. drive means for rotating said transport bowl, d. passage means for conducting mixture from said hopper into the transport bowl, e. pneumatic means for expelling the cement mixture from said transport bowl, f. an auxiliary hopper for holding accelerator material to be added to the cement mixture in the machine, g. and valve means operatively connected to said drive means for coordinating the rate of flow of cement accelerator material with the rotation of said transport bowl. 